static <A> L<A> subList_cloneIfDifferent(L<A> l, int startIndex, int endIndex) {
  L<A> l2 = subList(l, startIndex, endIndex);
  ret l == l2 ? l : cloneList(l2);
}

static <A> L<A> subList_cloneIfDifferent(L<A> l, int startIndex) {
  L<A> l2 = subList(l, startIndex);
  ret l == l2 ? l : cloneList(l2);
}